Carbide-Derived Niobium Pentoxide with Enhanced Charge Storage Capacity for Use as a Lithium-Ion Battery Electrode,ACS Applied Energy Materials

当前位置： X-MOL 学术 › ACS Appl. Energy Mater. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Carbide-Derived Niobium Pentoxide with Enhanced Charge Storage Capacity for Use as a Lithium-Ion Battery Electrode
ACS Applied Energy Materials ( IF 5.4 ) Pub Date : 2020-04-15 00:00:00 , DOI: 10.1021/acsaem.9b02549
Ö. Budak _{1,

2} , M. Geißler ₃ , D. Becker ₄ , A. Kruth ₅ , A. Quade ₅ , R. Haberkorn ₄ , G. Kickelbick ₄ , B. J. M. Etzold ₃ , V. Presser _{1,

2}

Affiliation

Nb₂O₅ has been explored as a promising anode material for use as lithium-ion batteries (LIBs), but depending on the crystal structure, the specific capacity was always reported to be usually around or below 200 mAh/g. For the first time, we present coarse-grained Nb₂O₅ materials that significantly overcome this capacity limitation with the promise of enabling high power applications. Our work introduces coarse-grained carbide-derived Nb₂O₅ phases obtained either by a one-step or a two-step bulk conversion process. By in situ production of chlorine gas from metal chloride salt at ambient pressure, we obtain in just one step directly orthorhombic Nb₂O₅ alongside carbide-derived carbon (o-Nb₂O₅/CDC). In situ formation of chlorine gas from metal chloride salt under vacuum conditions yields CDC covering the remaining carbide core, which can be transformed into metal oxides covered by a carbon shell upon thermal treatment in CO₂ gas. The two-step process yielded a mixed-phase tetragonal and monoclinic Nb₂O₅ with CDC (m-Nb₂O₅/CDC). Our combined diffraction and spectroscopic data confirm that carbide-derived Nb₂O₅ materials show disordering of the crystallographic planes caused by oxygen deficiency in the structural units and, in the case of m-Nb₂O₅/CDC, severe stacking faults. This defect engineering allows access to a very high specific capacity exceeding the two-electron transfer process of conventional Nb₂O₅. The charge storage capacities of the resulting m-Nb₂O₅/CDC and o-Nb₂O₅/CDC are, in both cases, around 300 mAh/g at a specific current of 10 mA/g, thereby, the values are significantly higher than that of the state-of-the-art for Nb₂O₅ as a LIB anode. Carbide-derived Nb₂O₅ materials also show robust cycling stability over 500 cycles with capacity fading only 24% for the sample m-Nb₂O₅/CDC and 28% for o-Nb₂O₅/CDC, suggesting low degree of expansion/compaction during lithiation and delithiation.

中文翻译：

具有增强的电荷存储能力的碳化物衍生的五氧化二铌，用作锂离子电池电极

Nb ₂ O ₅已被用作锂离子电池（LIB）的阳极材料，但根据晶体结构的不同，通常报道其比容量通常在200 mAh / g左右或以下。我们首次提出了粗晶粒Nb ₂ O ₅材料，该材料大大克服了这种容量限制，并有望实现高功率应用。我们的工作介绍了通过单步或两步本体转化过程获得的粗晶碳化物衍生的Nb ₂ O ₅相。通过在环境压力下从金属氯化物盐原位生产氯气，我们仅需一步即可直接获得正交晶态Nb ₂ O₅与碳化物衍生的碳（o-Nb ₂ O ₅ / CDC）并存。在真空条件下由金属氯化物盐原位形成氯气会产生CDC，覆盖剩余的碳化物核，在CO ₂气体中进行热处理后，CDC可以转化为被碳壳覆盖的金属氧化物。两步法得到具有CDC的混合相四方和单斜Nb ₂ O ₅（m-Nb ₂ O ₅ / CDC）。我们结合的衍射和光谱数据证实了碳化物衍生的Nb ₂ O ₅材料显示由于结构单元中的氧缺乏而引起的晶面混乱，对于m-Nb ₂ O ₅ / CDC，则存在严重的堆垛层错。这种缺陷工程可以提供比常规Nb ₂ O ₅的双电子转移过程更高的比容量。在两种情况下，得到的m-Nb ₂ O ₅ / CDC和o-Nb ₂ O ₅ / CDC的电荷存储容量在10 mA / g的比电流下均为约300 mAh / g，因此，其值为明显高于Nb ₂ O ₅作为LIB阳极的最新技术水平。硬质合金铌₂ O ₅材料在500个循环中也显示出强大的循环稳定性，样品m-Nb ₂ O ₅ / CDC的容量仅下降24 ％，o-Nb ₂ O ₅ / CDC的容量仅下降28％，表明在此过程中膨胀/压实度低锂化和脱锂。

更新日期：2020-04-15

点击分享查看原文

点击收藏

阅读更多本刊新发论文本刊介绍/投稿指南